Painful Speed Bumps? Could Be Appendicitis

Diagnostic uncertainty surrounding appendicitis could turn into a small bump in the road, according to a study showing a high correlation between appendicitis and pain on driving over speed bumps on the way to the hospital.

Of 64 patients with suspected acute appendicitis, 54 had worsening pain when traveling over speed bumps (speed-bump positive). Subsequently, 34 of the 54 patients were found to have histological proven appendicitis, and 33 of the 34 had positive speed-bump tests, reported Helen Ashdown, BM BCh, of the University of Oxford in England, and colleagues in BMJ.

Of the remaining speed bump-positive patients without appendicitis, seven had serious abdominal conditions, such as ruptured ovarian cysts and diverticulitis.

"Presence of pain while traveling over speed bumps was associated with an increased likelihood of acute appendicitis," Ashdown's group wrote. "As a diagnostic variable, it compared favorably with other features commonly used in clinical assessment. Asking about speed bumps may contribute to clinical assessment and could be useful in telephone assessment of patients."

Rapid diagnosis and treatment are the key factors in successful outcomes in acute appendicitis. Delayed surgical intervention risks appendiceal perforation, which can lead to peritonitis, sepsis, and even death. Unfortunately, as many as 40% of appendectomies reveal a normal appendix, a negative rate associated with considerable morbidity and cost, the authors noted.

In its early stages, appendicitis represents an especially vexing diagnostic challenge, usually associated with nonspecific signs and symptoms. Various elements of the patient's medical history, physical exam, and laboratory findings occasionally provide some guidance and have formed the basis for several clinical algorithms and scoring systems, none of which has proven to be consistently accurate, the authors continued.

Beginning with chance observations and anecdotal reports, Ashdown and colleagues examined the potential value of worsening abdominal pain when traveling over speed bumps as a diagnostic aid for appendicitis. They conducted a prospective study of adult patients referred to the on-call surgical team at a general hospital for suspected appendicitis.

Participating patients completed a questionnaire that included items related to their level of pain during the trip to the hospital. Patients with pain that worsened when the vehicle went over speed bumps were classified as speed-bump positive. Those who felt no change in pain or could not remember, were classified as speed-bump negative.

All participants completed the survey withing 24 hours after arriving at the hospital and prior to going to the operating room (if they had surgery). For patients who underwent surgery, the final pathology report served as the standard for diagnosis of appendicitis.

Ashdown and co-authors reported findings for 101 patients, who had a median age of 34. Medical records showed that 61 patients went to the operating room, and the appendix was removed from 54 patients.

The analysis of speed-bump accuracy as a diagnostic aid involved 64 patients who recalled traveling over speed bumps on the way to the hospital. The questionnaires showed that 54 of the 64 patients tested speed-bump positive.

Of 34 patients with pathology-confirmed appendicitis, 33 had positive speed-bump tests, resulting in a sensitivity of 97%, specificity of 30%, positive-predictive value of 61%, and negative-predictive value of 90%. The likelihood ratio was 1.4 for a positive test result and 0.1 for a negative result, the authors said.

Ashdown and colleagues performed a second analysis that included the seven patients who had pain on traveling over speed bumps but had diagnoses other than appendicitis. That study resulted in a sensitivity of 98% and specificity of 39% for the speed-bump test.

The authors noted that 33 patients did not recall whether they traveled over speed bumps on the way to the hospital. Including them in the primary analysis reduced the speed-bump test sensitivity to 77% and increased specificity to 61%.

Results with the speed-bump test compared favorably with those of commonly used clinical indicators of acute appendicitis:

Speed bump test: 97% sensitivity and 30% specificity

Migratory pain: 65% and 33%

Nausea/vomiting: 79% and 17%

Rebound tenderness: 71% and 50%

The authors concluded that the high sensitivity of the speed-bump test makes it a potentially useful tool for ruling out appendicitis and possibly other abdominal diagnoses. The low specificity, however, means that a substantial number of patients with increased pain over speed bumps will not have appendicitis on further evaluation.

"Our findings suggest that questioning about speed bumps should form a routine part of the assessment of patients with possible appendicitis," Ashdown's group concluded. "Unanswered questions include whether the speed or manner of driving approach to a speed bump affects the diagnostic power."

Other study limitations included possible recall bias and a smaller patient population than originally planned for after a hospital site redevelopment led to changes in speed bump availability.

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